I unlocked & completed it today, I have both a DS3 and a G25, I had never used the G25 with PS3 till today though. Spend 2 hours with the DS3 not even making the 2 laps on any of the tracks.
Set up the G25. Spend around 1 hour finding the FFB and assists settings that worked for me and got a bit used to the handling in GT5, after that it took me around 90 minutes total to get bronze in all 3. Can't see myself even getting silver in these without a serious amount of effort.